, 2007), a variety of different illegal drug user populations (Stanford et al., 2009) and somewhat consistent with aspects of personality in chippers (Kassel, Shiffman, Gnys, Paty, & Zettler-Segal, 1994). Second, consistent with studies in experimental animals (Belin et al., 2008) and our observations with www.selleckchem.com/products/ABT-888.html humans smokers (Hogarth et al., 2010; Hogarth, 2011), BIS-11 scores significantly predicted the presence of two symptoms of tobacco dependence (DSM5 and DSM7), which might be reflective of habitual smoking behavior. DSM5 was assessed by the endorsement of finding oneself chain smoking or similar. Although chain smoking might reflect a heightened incentive value of cigarettes, we suspect, due to the emphasis of the phrase ��find yourself�� in the question, that smoking might be automatized in individuals who endorse this symptom.

DSM7 reflects continued smoking despite health problems or other negative consequences, such as depression or anxiety. Again, endorsement of such a symptom is suggestive of an inflexible relationship between consumption and the current value of the drug and accords the observation that impulsivity is associated with perseveration of drug self-administration despite shock punishment in rodents (Belin et al., 2008; Economidou, Pelloux, Robbins, Dalley, & Everitt, 2009). Nevertheless, the negative consequences of drug seeking are manifest within this paradigm (discrete and immediate) somewhat differently to how a smoker might experience them (typically sustained and slower). Both future human and animal work might attempt to identify the range of negative consequences to which drug seeking is insensitive.

However, the notion that impulsivity might also influence the rewarding aspects of nicotine is not ruled out by our findings. In particular, we also observed that BIS-11 scores showed modest but significant associations with a variety of measures of tobacco use and dependence (see also Spillane, Smith, & Kahler, 2010). Furthermore, it is possible that aspects of chain smoking and/or perseverative drug use might also reflect heightened drug reward. Another limitation of the study is that the BIS-11 likely reflects trait impulsivity, which itself has an uncertain relationship with other measures of the construct including inhibitory control or delay discounting, and the degree to which our findings are specific to the BIS-11 deserves further examination.

Summary We observed that impulsivity was particularly predictive of the endorsement of symptoms of dependence suggestive of the development of automatized or habitual smoking. These data support the view that impulsivity plays a role in hastening the transition to habitual nonintentional Entinostat control over drug seeking and hence the clinical perseveration of this behavior.